Various systems provide electrostatic imaging using charged photoreceptor plates which have been exposed to x-ray radiation to form latent x-ray images. The radiation sensitive imaging plates normally comprise conductive and insulative layers. A frequent selection of material for a conductive surface layer of the plates is selenium. The devices use the selenium as an active surface layer from which a focused laser beam is able to develop a readout signal having a magnitude related to x-ray exposure. This is accomplished by creating relative scanning motion between the laser output device, such as a conductively coated electrode strip, and the surface of the imaging plate.
The size of the plates used are often quite large, which requires lengthy conductive strips. A typical length of a strip, which is about equal to the width of the related photoconductor surface, is approximately 356 millimeters (14 inches). A typical length of an x-ray plate photoconductor is about 432 millimeters (17 inches). A glass strip electrode will scan slowly with a mechanical motion along the long axis of the x-ray plate, which is generally the vertical dimension of the x-ray image, while a focused laser beam scans at high speed along the shorter axis of the plate, which is the horizontal dimension of the image. The spacing between the strip and the photoconductor plate surface must be small to achieve optimum reproduction of the latent image.
One example of a multilayered imaging device and scanner is disclosed in U.S. Pat. No. 4,176,275 to Korn et al. In another example, U.S. Pat. No. 4,961,209 to Rowlands et al, a sensor electrode comprises a metal strip with a longitudinal slit to allow passage of a laser beam therethrough.